Amber glass and batch composition for making same



batch composition for producing the compositions of Table I are set forth in Table II, the correspondlng glass compositions and batches being identified by the letters A, B, C, D and E, respectively.

Compositions of amber glass 'mais v11 2 Batch'esor amber gloss compositionsof Tali'lel Material *A B vo' Fluorspar Powdered Cha oal Suliur.

In Table I, the percentages ofconstituents were calculated from analyses of the .raw materials with the exception of the iron content which wasV determined by chemical analysis.

It will be noted from Tables I and II thatno ironcompound is speciiied in the batch Vand that the iron lcontent of the glass compositions is-limitedto the prescribed maximum of approximately 0.10% (expressedas F6203), which, in prioramf ber glasses maybe as high as 0.40%. f

. Contrary to. the belief. in the prior art that the vsubstantial addition of iron'Y is necessary` for theA production of carbon-sulfur .am-bers,` good strong amber coloration has been obtained in glassmade accordingto .this invention and containing less than 0.05% (FezOs).

Table I omits the percentages of S and C'which are present in the glass in small amounts, corresponding to the amounts present in the batchl as shown by Table'III.' Sulfur isjderived from the barytesv of Example A, Table II, and in gen-fA eral, may be derived from any suitable vsulfur compound such as asulfate or a'sulde, excluding iron compounds.` v A Fluorine, also present in small amount 'in most of, the examplesj'is as a 'matter of convenience expressed as calcium fluoridefand if introduced, mayfbe incorporated in any suitable'forml of fluoride'otherth'an fluorspar, if desired. The use of a fluoride is preferred because of its' effectiveness as a ining agent and color intensiiier in the glass and batch of this invention. Also, I have Adiscovered that introducing fluorine in reduced amber glass decreases the transmission vof 'ultraviolet light. However, as shown by Example B; Tables I and II, the invention is not limited to glass containing fluorine or to a batch 'containing va uoride. If a fluoride is used, not less than 10 pounds offluorspar or 'its equivalent' in fluoride content per 1000 lbsjof sand is'necessary to vintensify Y 4 color but no advantage is obtained in using more than 30 pounds per 1000 lbs. of sand. Therefore,

' the preferred content of iluorspar is 10 to 30 lbs.

per 1000 lbs. of sand or the equivalent content of other suitable fluoride.

The amount of sulfur by Weight' preferably equals .or exceeds the amount of carbon-by weight in the batch. The powdered charcoal may be re- *placed by such other reducing agentsY as powderedr, coal, graphite or powdered aluminum. I

Y have found xthat a reduction in ultraviolet transmission is obtained by increasing the amount of vcarbon without a corresponding decrease in transmission of visible light such as occurs with addition of iron.

. vIn producing my'novel glass, the compositions furnace, furnace atmosphere and temperature,

without departing from the invention ordisccvery. if lNo oxidizingagents are present vintheexam- Dlesof Tables I'andII.

The 'batch and. glass of the examples are easy to melt 'and fine and may be produced-in ordi; naryfurnaces at temperatures ranging from approximately 2500 to approximatelyy 2900n F. without blistering or foaming. 'I'he glass remainsstad ble over long periods of'timeat'furnace tempera- The stability vof my novel glass' makes possibl for'the iirst time the production of'reduiced: or carbon-sulfur amber glass through a wide range of color including light shades, characterizedA by attractive golden or golden tinted yellow o1' golden red -coloration. 1 This lcontrasts sharply wi'th prior amber glass 'which'is too unstable'to permit very much lightening of color and which,' when light` ening is attempted, has an unattractive dull green-yellow color. Also, my novel glassls dis"r tinguished from prior amber glass-by increased transparency and a red cas-t which are desirable suii'iciently-k low transmission of ultraviolet?'lightv to adequately protectthe contents of containers composed ofit and a relatively high transmissionv of visible light which permits the contents to be seen-and 'attainment of a denite and pleasingArk redcast.V Thus, glass embodying'm'y invention 'or discovery may have a higher eiciency withfre' spect to the ratio of Visible to ultraviolet trans-4 mission or may be more efc'ient in transmitting visible light than prior amber glass. Also; "glassf of 'rny invention may have as low atrans-mission of ultraviolet light as prior amber glass The low ultraviolet transmission of reduced amber glass of my invention or dscoveryri's remarkable in three respects: first because'attained- Without the addition ofiron to the batch, that is',v with the low content of iron (expressed asfFezOs) specied above, which results in the improvedV transmission of visible light and in coloration'vjva's: explained above; second, because of the vdiscovery that' ultraviolet transmissionl can be reduced V`by! the addition ofv carbonv and Withoutthe' additioni of iron as in prior amber glass; third, because of the discovery that ultraviolet transmission can be reduced by introducing fluorine into amber glass of the reduced or carbon-sulfur type.

My discoveries also make possible for the rst time the production of reduced or carbon-sulfur amber glass of good chemical durability in light shades or of good transparency to visible light without danger of loss of color or of blistering and foaming in melting and iining. Example D is Irepresentative of this accomplishment.

Having thus described my invention or covery, what I claim is:

1. An amber glass of the reduced type containing sulfur as colorizing material and comprising by weight 70-80% S102, 11i-17.5% alkali. 1.3-13% CaO iron expressed as Fe203 not exceeding 0.10% and a small amount of fluorine, said glass having a K value of 45-60 where K equals the percentage of S102 minus twice the percentage of alkali.

2. An amber glass o the reduced type containing sulfur as colorizing material and comprising by weight approximately 70-80% S102, lil-17.5% alkali, 1.3-13% CaO, 0 to 6.5% MgO, 0.5-5% A1203, iron expressed as Fe2Oa not exceeding 0.10% and the balance minor constituents selected from the class consisting of BaO, B203, F2, Ti02 and SrO, said glass having a K value of L15-60 where K equals the percentage of S102 minus twice the percentage of alkali.

3. An amber glass of the reduced type containing carbon and sulfur and comprising 70-80 S102, 10-17.5% alkali, 1.3-13% CaO, 0-6.5% MgO, 0.55% A1203, 0.02-0.10% iron expressed as Fe203, and a small amount of iiuorine, and having a K value of 45-60 where K equals the percentage of Si02 minus twice the percentage of alkali.

4. A batch for making a reduced amber glass comprising sand, alkali, calcia and alumina bearing minerals, a reducing agent and sulfur, and a fluoride, said ingredients being s selected and proportioned as to form a glass of the desired coloration containing approximately by weight dis- 7o-so% S102, 1o 1'1.5% aikan, 1.313% Cao, iron expressed as Fe20s not exceeding 0.10% and a small amount of iiuorine, and having a K value of Ll-60 where K equals the percentage of SiOz 5 minus twice the percentage of alkali.

5. A batch for making a reduced amber glass comprising sand, alkali, calcia, sulfur, a reducing agent and alumina bearing minerals, said ingredients being so selected and proportioned as to form amber glass of the desired coloration containing approximately by Weight 70-80% Si02, 1017.5% alkali, 1.3-13% CaO and iron expressed as FezOs not exceeding 0.10% and wherein an iron compound as a stabilizer and ning agent is replaced by further proportioning said ingredients so that the percentage of S102 minus twice the percentage of alkali equals 45-60 and by the addition to the batch of a small annount of nuoride.

AARON K. LYLE.

REFERENCES CITED The following references are of record in the iile of this patent:

UNITED sTATEs PATENTS Number Name Date 1,830,902 Hood Nov. 10, 1931 2,056,627 Smelt Oct. 6, 1936 2,303,779 West Dec. 1, 1942 2,367,871 Kalsing et al J an. 23, 1945 FOREIGN PATENTS 5 Number Country Date 3 142,393 switzerland 1930 OTHER REFERENCES 

